powershell6.rb: fix for new style
powershell6.rb: fix for new style

404NetworkError/homebrew-versions,pkq/homebrew-versions,pkq/homebrew-versions,caskroom/homebrew-versions,404NetworkError/homebrew-versions,mahori/homebrew-cask-versions,caskroom/homebrew-versions,rogeriopradoj/homebrew-versions,rogeriopradoj/homebrew-versions